2016 November – Major incident!!

Posted by on March 29, 2017

Seawind owners! Exercise EXTREME CAUTION when filling your freshwater tank. Learn from our mistake.

We were at the dock, and Colleen was enjoying a nice warm shower (thanks to our Webasto diesel-powered heater) when that distinctive running-out-of-water sound started coming from the pump. Helpful as always, I jumped off, started the hose at about 1/3 strength, and put the nylex hose fitting into the filler. Then forgot about it!

I went out to a social event in Melton, and Colleen popped off to work for a three hour shift. Time passed… water trickled…

Colleen arrived back at the boat to find it on a distinct lean! There was an inch of water above the floor on the port side. She called for assistance and dove for the manual bilge pump and started pumping. Phoning a marina buddy for assistance, the situation soon escalated and Water-police and firemen were soon on the scene. Another marina resident spotted the still-running tap and shut it off, and using a portable pump from the firemen, the boat was soon on an even keel.

Here’s what happened. The tank must have been leaking a very tiny bit, as the bilge pump on that side kept tripping off. High up on the list of things to do was to investigate that leak and fix it, but in the meantime the bilge pump was disconnected and manually operated once a week or so to empty the bilge and stop waking everyone up the middle of the night.

Instead of the excess water overflowing or exiting through the breather hose, the fitting had stuck fast in the filler. The tank had pressurised, opening up the a small crack where the cover of the tank met the hull, and with the pressure of the hose the crack was large enough to let a fair bit of water through.

The freshwater tank on an 1160 is a complex beast, and is made up of three parts. You have a rectangular prism from seat level down to the sub-floor, joining another rectangular prism, then joining the pod which hangs under the bridge-deck. The top of the pod is a sheet of fibreglass over the top, glassed in well. Seawind have made a few changes over time to try to improve the strength of this assembly, but at the time Xtsea was built (hull #22) that was the extent of things. As the two hulls of the catamaran flex at sea, this puts a twisting force across the hull, and tanks split.

The problem of freshwater tanks leaking is one that quite a few early hulls have encountered. I saw an 1160 with the issue up in Airlie Beach at one time and it looked like a huge job. Bill and Linda on About Time who were in the same marina had it happen to them, and I have heard of four or five others.

The repair is simple in principle, but to do a good job of it is very time consuming and sourcing replacement flooring is expensive and difficult. Seawind have a document detailing what needs to be done.

Using a good orbital jigsaw, I cut a hole in the floor as detailed in the document, with rounded edges to improve the strength of the corners. Note that the depth of cut along the couch has to be reduced to miss the second part of the tank there. Just cut your jigsaw blade shorter with an angle grinder.

Then lift out the floor you have cut. My job was a bit harder as I had to remove the floor with the table attached as I had glued it in place with industrial mortar on an earlier repair and it wasn’t going anywhere!

The top of the tank was then exposed. An angle-grinder with a sanding attachment helped grind back the flange to give something for the resin to grab, then I slopped on lots of vinylester resin and glass matting. Vinylester was the product suggested by Seawind instead of epoxy resin to have similar bond strength.

Filling up to recheck the repair, I was staggered to see the amount of flex in the lid of the tank. Seawind’s document suggested adding a stringer, but I put in two to be sure. More glassing and matting all round as I did not want to have to do this a second time.

Repair to tank completed, stringers installed, and ply and formica flooring removed.

The tank was now watertight again, but now to make everything beautiful! I elected to remove the entire floor as I didn’t want anything to mar the surface. Above the actual fibreglass was plywood with formica on top. By using a circular saw with depth of a few millimetres, I was able to cut the floor into 25mm squares and pry up the small pieces. Whatever glue they were using was a good one!

I also removed the beam along the doorway and a vertical trim each side. I would have to remake these later. With the old floor up, I had to clean off the glue residue. Some elbow grease and sandpaper.

We discovered that the barge boards were not installed in newer boats, and decided that we would prefer not to have them as they make the floor that much neater and we have never had a drop of water come in from behind. That meant making up new top steps and rebating them so that the new plywood base would overlap the step for strength. Had to find some 25mm marine-ply to do that, and some artistic use of Brian’s tools.

Then I sourced some plywood, but as I needed to span 2700mm I had to get some special sized gear. It was soon cut and glued down with Sikabond T55. Now for the nice stuff..

Luckily Bill and Linda had some flooring left over from their repair. They had to import it from the UK as it was not available here. It was Formica in a Holly and Teak pattern (could be product code FE070) in sheets of 2440 x 1300mm. It was in pretty bad condition as the contractor had left it to rot, but happily I was able to have the ends and sides trimmed of most of the cracks.

After waiting most of a month for ‘experts’ to do the final cutting and fitting, time was running out so I went down to Bunnings and purchased a laminate trimming router and Gavin (Lauren Marie 1250) and I managed to do it ourselves. Millimetre perfect too!

Ply glued down, new steps in place, and gluing the formica into place.

Final piece of Formica down

The beam and trims were made, sealed and clear-coated, and installed and look fantastic. Brian suggested I put a layer of fibreglass matting on the beam to protect it from footwear and he said a single layer would be transparent, which it pretty well is.

Final step was putting trims on the new top steps. How do you clamp a distance of nearly 3 metres? With rope and strings!

Attaching trims on the top steps with a string-clamp

The final clearcoat went on towards the end of March after four months of hassle and I could finally put all the tools away. We got out of this very cheaply by doing everything ourselves and with donated flooring, but it was an absolute bastard and I would not want to do it again.

Finished job. Never again hopefully.

Lesson learned. Watch out for your watertank!

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